On Tuesday, several hundred Islamists armed with knives and sticks charged a gathering of members of the UGTT union in the capital and broke office windows with stones. Police had to intervene to separate the two groups.

“The UGTT decided to go on strike on December 13, after the attack on the central trade unions and trade unionists on Tuesday,” the union said in a statement on Wednesday.

“The UGTT (General Union of Tunisian Workers) has decided that a general strike will take place on Thursday, December 13, across Tunisia,” it told AFP.

It called the strike to protest an attack on Tuesday against a UGTT demonstration blamed by the union on supporters of the Islamist ruling party.

A union leader told AFP the UGTT demands the dissolution of the League for the Protection of the Revolution. It accuses the group, close to the ruling Ennahda party and with a reputation for brutal violence — of Tuesday’s attack.

The nationwide strike call is only the third to be made by the powerful UGTT since its foundation in the 1940s.

The first was in 1978 and the second work on January 12, 2011 — two days before the fall of Zine El Abidine Ben Ali’s regime.

On Tuesday, several dozen assailants attacked members of the UGTT, who were gathered outside the union’s headquarters in Tunis to mark the 60th anniversary of the assassination of its founder, Farhat Hached.

Police intervened to separate the two sides, but 10 demonstrators were wounded in the attack, according to the trade union.

Tunisia Live reports that opposition members of the National Constituent Assembly (المجلس الوطني التأسيسي التونسي, Assemblée constituante tunisienne) have called for a 3 day boycott of its plenary proceedings in solidarity with the UGTT.

It will be interesting to see how the junior member of the Ennahda government, the Democratic Forum for Labour and Liberties (Arabic: التكتل الديمقراطي من أجل العمل والحريات‎, at-Takattul ad-Dīmuqrāṭī min ajl il-‘Amal wal-Ḥurriyyāt ; Ettakatol – Forum démocratique pour le travail et les libertés) which has observer status to the Second International, will react to this latest act by Islamist thugs.

President Moncef Marzouki has recently called for a smaller Cabinet of technocrats to deal with the crisis.

“The once savagely repressed progressive Islamist party An-Nahda won the Tunisian elections this week on a platform of pluralist democracy, social justice and national independence. Tunisia has faced nothing like the backlash the uprisings in other Arab countries have received, but that spirit is the driving force of the movement for change across a region long manipulated and dominated by foreign powers.”